{"id":1211,"date":"2016-10-03T16:37:54","date_gmt":"2016-10-03T15:37:54","guid":{"rendered":"https:\/\/blogs.bmj.com\/sti\/?p=1211"},"modified":"2016-10-03T16:37:54","modified_gmt":"2016-10-03T15:37:54","slug":"cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/sti\/2016\/10\/03\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\/","title":{"rendered":"Cochrane says: Chlamydia screening may have very limited impact, but more research is needed"},"content":{"rendered":"<p>There is a strong rationale for systematic Chlamydia screening, and it is widely recommended and practised. Yet there are harms associated with the screening process (<a href=\"http:\/\/sti.bmj.com\/content\/82\/2\/97.full\">Low(STIs)<\/a>), and, of course, serious concerns about its cost-effectiveness (<a href=\"http:\/\/sti.bmj.com\/content\/91\/6\/423.abstract?sid=39999bdb-27e5-4bff-8836-d9d6739aa5ce\">De Wit &amp; Kretzschmar (STIs)<\/a>).\u00a0 This lends urgency to the question of whether Chlamydia screening works \u2013 addressed in a recently published systematic review for the Cochrane Database:\u00a0 <a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/14651858.CD010866.pub2\/full\">&#8216;Screening for genital chlamydia infection&#8217;<\/a>.<\/p>\n<p>It all depends, the authors claim, on what we want screening to do: whether it\u2019s a general reduction of prevalence in the population that we\u2019re aiming at, or the prevention of serious <em>sequelae<\/em> such as PID (Pelvic Inflammatory Disease) in individuals.\u00a0 The strict Cochrane exclusion criteria (especially that of \u2018reporting a pre-specified primary outcome\u2019) reduce the pool of evaluated studies to just <strong>two<\/strong> addressing the impact of screening on Chlamydia prevalence \u2013 only <strong>one<\/strong> of which (not, as it happens, an RCT) addresses impact on prevalence in the general population (<a href=\"http:\/\/sti.bmj.com\/content\/87\/Suppl_1\/A45.2.abstract?sid=8147c32c-1880-4766-8095-b551e4ee9b82\">Schmid &amp; Kretzschmar (STIs)<\/a>).\u00a0 Regarding the impact of screening on reduction of PID incidence, the field narrows to just <strong>four <\/strong>RCTs (<a href=\"http:\/\/sti.bmj.com\/content\/87\/2\/156.abstract?sid=0570f309-4da6-426f-889d-8ca2654b9150\">Andersen &amp; Olesen (STIs)<\/a>; \u00a0<a href=\"http:\/\/cid.oxfordjournals.org\/content\/31\/4\/951.full\">Ostergaard &amp; Olesen<\/a>; <a href=\"http:\/\/www.bmj.com\/content\/340\/bmj.c1642\">Oakeshott &amp; Hay<\/a>; <a href=\"http:\/\/www.nejm.org\/doi\/full\/10.1056\/NEJM199605233342103#t=article\">Scholes &amp; Stamm<\/a>).<\/p>\n<p>Respecting the impact on prevalence, <a href=\"http:\/\/sti.bmj.com\/content\/87\/Suppl_1\/A45.2.abstract?sid=8147c32c-1880-4766-8095-b551e4ee9b82\">Schmid &amp; Kretzschmar (STIs)<\/a> observe very little effect (RR <strong>0.96<\/strong>), but the quality of evidence is rated, on Cochrane criteria, as \u2018low\u2019.\u00a0 As for PID prevention, an effect was observed (overall RR <strong>0.68<\/strong>), but unfortunately was considerably less pronounced in the two studies with low risk of selection bias (<a href=\"http:\/\/sti.bmj.com\/content\/87\/2\/156.abstract?sid=0570f309-4da6-426f-889d-8ca2654b9150\">Andersen &amp; Olesen (STIs)<\/a> and <a href=\"http:\/\/www.bmj.com\/content\/340\/bmj.c1642\">Oakeshott &amp; Hay<\/a>) (RR <strong>0.80<\/strong>) than with the other two studies ((RR <strong>0.42<\/strong>).\u00a0 This evidence was consequently downgraded from \u2018high\u2019 to \u2018moderate\u2019.<\/p>\n<p>So there continues to be no evidence at present for a positive impact of screening on general prevalence, though further research could possibly modify this assessment.\u00a0 As regards the incidence of PID, some limited degree of positive impact may have been demonstrated \u2013 though whether systematic screening interventions will turn out to be cost-effective is another question (<a href=\"http:\/\/sti.bmj.com\/content\/91\/6\/423.abstract?sid=39999bdb-27e5-4bff-8836-d9d6739aa5ce\">De Wit &amp; Kretzschmar (STIs)<\/a>).\u00a0 The reviewers point out there is another important trial that is still on-going (hence not eligible for inclusion): <a href=\"http:\/\/sti.bmj.com\/content\/91\/Suppl_2\/A3.2.abstract?sid=048efbbb-83c3-4194-9703-4716c4e2e528\">Hocking (STIs)<\/a>.\u00a0 The latter \u2013 a study being undertaken in Australian GP practices \u2013 involves \u2018opportunistic\u2019 testing (as defined by Low (<a href=\"http:\/\/sti.bmj.com\/content\/82\/2\/97.full\">Low(STIs)<\/a>) rather than screening proper (i.e. \u2018systematic\u2019 screening).\u00a0 However, given that this is the form of intervention being undertaken in many places including the UK, its final results will no doubt be of great interest.\u00a0 On the basis of the study\u2019s findings to date, the verdict seems unlikely to be favourable (<a href=\"http:\/\/sti.bmj.com\/content\/91\/Suppl_2\/A101.2.abstract?sid=e11888df-c0a7-45de-bbae-29e7ed78afde\">Yeung &amp; Temple-Smith (STIs)<\/a>).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>There is a strong rationale for systematic Chlamydia screening, and it is widely recommended and practised. Yet there are harms associated with the screening process (Low(STIs)), and, of course, serious concerns about its cost-effectiveness (De Wit &amp; Kretzschmar (STIs)).\u00a0 This lends urgency to the question of whether Chlamydia screening works \u2013 addressed in a recently [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/blogs.bmj.com\/sti\/2016\/10\/03\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":152,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2792,1648,599],"tags":[],"class_list":["post-1211","post","type-post","status-publish","format-standard","hentry","category-chlamydia","category-chlamydia-screening","category-screening"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Cochrane says: Chlamydia screening may have very limited impact, but more research is needed - Sexually Transmitted Infections<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blogs.bmj.com\/sti\/2016\/10\/03\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Cochrane says: Chlamydia screening may have very limited impact, but more research is needed - Sexually Transmitted Infections\" \/>\n<meta property=\"og:description\" content=\"There is a strong rationale for systematic Chlamydia screening, and it is widely recommended and practised. Yet there are harms associated with the screening process (Low(STIs)), and, of course, serious concerns about its cost-effectiveness (De Wit &amp; Kretzschmar (STIs)).\u00a0 This lends urgency to the question of whether Chlamydia screening works \u2013 addressed in a recently [...]Read More...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.bmj.com\/sti\/2016\/10\/03\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\/\" \/>\n<meta property=\"og:site_name\" content=\"Sexually Transmitted Infections\" \/>\n<meta property=\"article:published_time\" content=\"2016-10-03T15:37:54+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/2016\\\/10\\\/03\\\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/2016\\\/10\\\/03\\\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\\\/\"},\"author\":{\"name\":\"\",\"@id\":\"\"},\"headline\":\"Cochrane says: Chlamydia screening may have very limited impact, but more research is needed\",\"datePublished\":\"2016-10-03T15:37:54+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/2016\\\/10\\\/03\\\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\\\/\"},\"wordCount\":439,\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/#organization\"},\"articleSection\":[\"Chlamydia\",\"Chlamydia Screening\",\"Screening\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/2016\\\/10\\\/03\\\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\\\/\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/sti\\\/2016\\\/10\\\/03\\\/cochrane-says-chlamydia-screening-may-have-very-limited-impact-but-more-research-is-needed\\\/\",\"name\":\"Cochrane says: Chlamydia screening may have very limited impact, but more research is needed - 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